It is not big rig friendly -- drive slowly on those interior roads, with a spotter for the trees. But if the website says you can fit, you can rely on that info. I think you should have room for your rig and the tent. It is a lot cooler up there than in the valley -- bring sweatshirts and mosquito juice.
Also bring jerry cans for the water. There are faucets in the campground -- just fill your can, tote it back, dump it into the fill hole, repeat. Great exercise at 8000 feet!
The hiking in the high country near TM CG is world class. So are the flowers.
